Eunotosaurus

Eunotosaurus
Temporal range: Middle Permian, 265.8–259 Ma
Fossil specimen, on display at
Karoo National Park
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Reptiliomorpha
Clade: Amniota
Clade: Sauropsida
Genus: †Eunotosaurus
Seeley, 1892
Species:
†E. africanus
Binomial name
†Eunotosaurus africanus
Seeley, 1892

Eunotosaurus (Latin: Stout-backed lizard) is an extinct genus of amniote, possibly a close relative of turtles. Eunotosaurus lived in the late Middle Permian (Capitanian stage) and fossils can be found in the Karoo Supergroup of South Africa and Malawi. Eunotosaurus resided in the swamps of what is now southern Africa.[1] Its ribs were wide and flat, forming broad plates similar to a primitive turtle shell, and the vertebrae were nearly identical to those of some turtles. Accordingly, it is often considered as a possible transitional fossil between turtles and their prehistoric ancestors.[2][3] However, it is possible that these turtle-like features evolved independently of the same features in turtles, since other anatomical studies and phylogenetic analyses suggest that Eunotosaurus may instead have been a parareptile,[4] an early-diverging neodiapsid unrelated to turtles,[5] or a synapsid.[6]

  1. ^ Day, Mike; Rubidge, Bruce; Almond, John; Jirah, Sifelani (2013). "Biostratigraphic correlation in the Karoo: The case of the Middle Permian parareptile Eunotosaurus". South African Journal of Science. 109 (3/4): 4. doi:10.1590/sajs.2013/20120030. ISSN 0038-2353.
  2. ^ Cox, C.B. (1969). "The problematic Permian reptile Eunotosaurus". Bulletin of the British Museum of Natural History. 18: 167–196.
  3. ^ Benton, M.J. (2016). "The Chinese Pareiasaurs". Zoological Journal of the Linnean Society. 18 (4): 813–853. doi:10.1111/zoj.12389. hdl:1983/6d1a4f9b-a768-4b86-acb1-b3ad1f7ee885.
  4. ^ "The trouble with turtles: Paleontology at a crossroads". EARTH Magazine. Naomi Lubick. Retrieved 19 March 2014.
  5. ^ Simões, T. R.; Kammerer, C. F.; Caldwell, M. W.; Pierce, S. E. (2022). "Successive climate crises in the deep past drove the early evolution and radiation of reptiles". Science Advances. 8 (33): eabq1898. Bibcode:2022SciA....8.1898S. doi:10.1126/sciadv.abq1898. PMC 9390993. PMID 35984885.
  6. ^ Lichtig, Asher; Lucas, Spencer (2021). "Chinlechelys from the Upper Triassic of New Mexico, USA, and the origin of turtles". Palaeontologia Electronica. doi:10.26879/886. S2CID 233454789.